Microscope System for Fcs Measurements

ABSTRACT

A microscope system for conducting FCS measurements. The system includes an illuminating light source configured to emit an illuminating light at an illuminating wavelength. A target light source is provided and configured to emit a target light for marking an FCS volume in a sample volume at a target wavelength. The target wavelength differs from the illuminating wavelength. The system further includes a plurality of optical elements configured to direct the illuminating light and the target light onto the sample volume.

CROSS REFERENCE TO PRIOR APPLICATION

This is a U.S. national phase application under 35 U.S.C. §371 ofInternational Patent Application No. PCT/EP2006/066861, filed Sep. 28,2006, and claims benefit of German Patent Application No. 10 2005 046510.2, filed Sep. 29, 2005, which is incorporated by reference herein.The International Application was published in German on Apr. 5, 2007 asWO 2007/036559 A1 under PCT Article 21(2).

FIELD

The invention relates to a microscope system for FluorescenceCorrelation Spectroscopy (FCS) measurements, and in particular, to amicroscope system for conducting FCS measurements.

BACKGROUND

European Patent EP 0 941 470 describes a fluorescence correlationspectroscopy module for a microscope. The FCS module can additionally beconnected to a microscope of any desired design. Fluorescencecorrelation spectroscopy allows the investigation of molecular dynamicprocesses to be studied. For this purpose, the particles contained insolution are doped with fluorescent dyes, and these dyes are thenexcited by light of a particular wavelength. The excitation light comingfrom a laser is coupled into the module via a flange joint for anoptical waveguide. In the FCS module known from prior art, it isdifficult to align the FCS detection volume with the sample area, whichis to be investigated.

SUMMARY

In accordance with the present invention, a microscope system forconducting FCS measurements is provided. The microscope system includesan illuminating light source configured to emit an illuminating and atarget light source configured to emit a target light for marking an FCSvolume in a sample volume. The wavelength of the illuminating lightdiffers from the wavelength of the target light. The system also includea plurality of optical elements configured to direct the illuminatinglight and the target light onto the sample volume.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, the subject matter of the invention is illustratedschematically, and will be described in the following with the aid ofthe figures, in which:

FIG. 1 shows a schematic illustration of a first embodiment of theinvention; and

FIG. 2 shows a schematic illustration of a second embodiment of theinvention.

DETAILED DESCRIPTION

The present invention is directed to creating a microscope system whichcan be used to reliably perform the alignment with the sample volume tobe investigated. This can be achieved by a microscope system comprisingthe features described below.

In accordance with one embodiment of the invention the microscope systemfor conducting Fluorescence Correlation Spectroscopy (FCS) measurementscan be provided with a target light source for marking an FCS volume.Here, the light of the target light source can be also directed onto thesample volume via the plurality of optical elements. The wavelength ofthe first light source preferably differs from the wavelength of thetarget light source.

A combining element can be provided which combines the illuminatinglight of the first light source with the light of the target lightsource to form a common beam path. The light of the target light sourcepreferably has a longer wavelength than the illuminating light of thefirst light source.

In accordance with a further aspect of the present invention, the lightof the target light source can have a wavelength that is in the regionof red light. In the same way, the light of the target light source canhave a wavelength that is in the region of IR light. In the case of IRlight, a camera is provided which registers the IR light and converts itinto an image visible to the user. Furthermore, the target light sourceis preferably provided with a correcting optics in order to compensatechromatic aberrations due to the different wavelengths of the firstlight source and the target light source.

In accordance with yet a further feature of the one embodiment of thepresent invention, the first light source and/or the target light sourcecan include a laser.

In a further embodiment, the microscope is provided with an opticalfiber into which the illuminating light of the at least first lightsource and the light of the target light source can be coupled in orderto achieve the collinearity of the illuminating light and the light ofthe target light source. In this case, the combining element can includea beam splitter. Alternatively, the combining element can include anAOTF, an AOBS or an AOM.

Further advantageous refinements of the invention can be found in thediscussion below.

FIG. 1 schematically describes a microscope system 1 for conducting FCSmeasurements. The microscope system 1 is provided with at least onefirst light source 3 which emits illuminating light which is directedonto a sample volume 5 or a sample. Additionally, a target light source7 for marking the FCS volume 5 is provided. The target light source 7emits light 6, which is also directed onto the FCS volume. Thewavelength of the illuminating light 2 of the first light source 3differs from the wavelength of the light 6 of the target light source 7.The light 2 from the illuminating light source 3 and the light 6 fromthe target light source 7 are combined by a combining element 9 to forma common, collinear beam path. In this case, the combining element 9 canbe designed to include a beam splitter. Optionally, the combiningelement 9 can include an AOTF, an AOBS or an AOM. A correcting optics 10is provided between the target light source 7 and the combining element9, in order to compensate chromatic aberrations due to the differentwavelengths of the light 2 of the first light source 3 and the light 6of the target light source 7. The light 2 of the first light source 3and the light 6 of the target light source 7 is directed onto the samplevolume 5 or the volume via a plurality of optical elements 12 and amicroscope optics 14. The sample volume 5 or sample is preferablyprovided at least on an X-Y table 16, in order thereby to change thesample volume with respect to the position of the illuminating light.The sample volume 5 is excited to fluoresce due to the illumination bythe first light source 3, so that the sample volume 5 emits a detectionlight 15, which is also directed onto the detector 18 via the microscopeoptics 14 and the optical elements. The light 6 of the target lightsource 7 has a longer wavelength than the illuminating light 2 of thefirst light source 3. In a first embodiment, the light 2 of the targetlight source 3 has a wavelength lying in the region of red light. Thelocation of the light 6 of the target light source 7 on the samplevolume 5 can therefore be observed directly and visually by a user 24.If the light 6 of the target light source 7 lies in the wavelengthregion of IR light, a camera 22 is provided which produces an image forthe user 24, so that the latter can recognize the location of theilluminating light 25 in the sample volume 5.

FIG. 2 shows a further embodiment of the microscope system 1. Arrangeddownstream of the combining element 9 is an optical fiber 30 into whichthe illuminating light 2 of the at least first light source 3 and thelight 6 of the target light source are coupled. The collinearity of theilluminating light is achieved by coupling the illuminating light 2 ofthe light 6 of the target light source 7 into the optical fiber 30. Thisensures that the light 6 of the target light source 7 and theilluminating light 2 of the at least first light source 3 impinge on ashared impingement location 25 in the sample volume 5 or in the sample.The optical fiber 30 can be provided with a coupling-in optics 31 and acoupling-out optics 32.

1-10. (canceled)
 11. A microscope system for conducting FCS measurements comprising: an illuminating light source configured to emit an illuminating light having an illuminating wavelength; a target light source configured to emit a target light for marking an FCS volume in a sample volume and having a target wavelength, the target wavelength being different than the illuminating wavelength; and a plurality of optical elements configured to direct the illuminating light and the target light onto the sample volume.
 12. The microscope system of claim 11, further comprising a combining element configured to combine the illuminating light and the target light to form a common beam path.
 13. The microscope system of claim 11, wherein the target wavelength is longer than the illuminating wavelength.
 14. The microscope system of claim 13, wherein target wavelength is in a region of red light.
 15. The microscope system of claim 13, wherein the target light wavelength is in a region of IR light, the system further comprising a camera configured to detect IR light and convert the IR light into an image visible to a user.
 16. The microscope system of claim 11, wherein the target light source includes correcting optics configured to compensate for chromatic aberrations resulting from a difference between the target wavelength and the illuminating wavelength.
 17. The microscope system of claim 11, wherein at least one of the illuminating light source and the target light source includes a laser.
 18. The microscope system of claim 11, further comprising an optical fiber configured to receive the illuminating light and the target light so as to achieve a collinearity of the illuminating light and target light.
 19. The microscope system of claim 12, wherein the combining element includes a beam splitter.
 20. The microscope system of claim 12, wherein the combining element includes at least one of an AOTF, an AOBS, and an AOM.
 21. The microscope system of claim 12, wherein the target light source includes correcting optics configured to compensate for chromatic aberrations resulting from a difference between the target wavelength and the illuminating wavelength.
 22. The microscope system of claim 13, wherein the target light source includes correcting optics configured to compensate for chromatic aberrations resulting from a difference between the target wavelength and the illuminating wavelength.
 23. The microscope system of claim 15, wherein the target light source includes correcting optics configured to compensate for chromatic aberrations resulting from a difference between the target wavelength and the illuminating wavelength.
 24. The microscope system of claim 12, wherein at least one of the illuminating light source and the target light source includes a laser.
 25. The microscope system of claim 15, wherein at least one of the illuminating light source and the target light source includes a laser.
 26. The microscope system of claim 16, wherein at least one of the illuminating light source and the target light source includes a laser.
 27. The microscope system of claim 13, further comprising an optical fiber configured to receive the illuminating light and the target light so as to achieve a collinearity of the illuminating light and target light.
 28. The microscope system of claim 15, further comprising an optical fiber configured to receive the illuminating light and the target light so as to achieve a collinearity of the illuminating light and target light.
 29. The microscope system of claim 16, further comprising an optical fiber configured to receive the illuminating light and the target light so as to achieve a collinearity of the illuminating light and target light. 